1. Field of the Invention
The invention relates to an electric motor storing device for a hybrid vehicle that stores an electric motor, and in particular to a technique for suppressing occurrence of electrolytic corrosion that occurs in a first closed circuit that includes: an inner circumferential side rotational shaft disposed in a manner to penetrate an inner circumferential side of a rotor shaft of the electric motor; and a case, a second closed circuit that includes the rotor shaft of the electric motor and the case, and a third closed circuit that is branched from those closed circuits.
2. Description of Related Art
A hybrid vehicle that includes an electric motor storing device for a hybrid vehicle including: a case for storing an electric motor; a rotor shaft of the electric motor; an inner circumferential side rotational shaft disposed in a manner to penetrate an inner circumferential side of the rotor shaft has been known. One of such an example is an electric motor storing device for a hybrid vehicle in Japanese Patent Application Publication No. 2014-145476 (JP 2014-145476 A). The electric motor storing device for a hybrid vehicle in JP 2014-145476 A is configured by fastening a support member that rotatably supports the rotor shaft to the case.
FIG. 3 is an example of a drive apparatus 112 for a hybrid vehicle that includes a conventional electric motor storing device 110, such as that in JP 2014-145476 A. In this electric motor storing device 110, a rotor shaft 116 of an electric motor 114 is rotatably supported by a bearing 120 that is fixed to a support member 118 and a bearing 124 that is fixed to a case 122. An inner circumferential side rotational shaft 126 that is disposed in a manner to penetrate an inner circumferential side of the rotor shaft 116 is supported by a bearing 128 and a bearing 134 in a manner to be relatively rotatable to the rotor shaft 116, the bearing 128 being disposed between the inner circumferential side rotational shaft 126 and the support member 118, and the bearing 134 being interposed between the rotor shaft 116 and a carrier shaft 132 of a planetary gear device 130 that is spline-fitted to an end of the inner circumferential side rotational shaft 126 on an opposite side from the support member 118. A stator 136 of the electric motor 114 is fixed to the case 122 by a fastening bolt 138. The support member 118 is fastened to an inner wall of the case 122 by a fastening bolt 140.